JP2008196316A - Starting control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve starting performance by suppressing the racing of an engine. <P>SOLUTION: A starting control device of an internal combustion engine has a variable valve gear, which comprises a lift and operating angle variable mechanism capable of simultaneously and continuously increasing and decreasing a lift and an operating angle of an intake valve and a phase variable mechanism capable of advancing and retarding the phase of a lift center angle of the intake valve and which can vary and control valve timing of the intake valve, and controls an amount of intake air flowing in a cylinder with the variable valve gear. The starting control device comprises a starting rotation speed control means (S316) for controlling the valve timing of the intake valve to starting valve timing at which the lift and the operating angle are a small lift and a small operating angle and closing timing is near a bottom dead center. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a start control device for an internal combustion engine.

A conventional start control device for an internal combustion engine feedback-controls ignition timing so that the engine speed converges to a target idle speed based on the integral value of the amount of engine speed when starting the engine (for example, patents) Reference 1).
JP 2004-108172 A

  However, the above-described conventional start control device for an internal combustion engine reduces the rotational surcharge by torque control by the ignition timing retard according to the integral value of the rotational surplus amount at the time of engine start. For this reason, there is a problem in starting performance such as vibration and noise at the time of starting the engine, since it becomes a suppression after the occurrence of rotational blow-up.

  The present invention has been made paying attention to such a conventional problem, and an object of the present invention is to improve the start-up performance by suppressing the rotational blow-up at the start of the engine.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected, it is not limited to this.

  According to the present invention, the lift operating angle variable mechanism (110) capable of simultaneously and continuously expanding and reducing the lift and operating angle of the intake valve (35), and the phase of the lift center angle of the intake valve (35). And a variable valve mechanism (100) capable of variably controlling the valve timing of the intake valve (35) provided with a phase variable mechanism (140) capable of being retarded. A start control device for an internal combustion engine (1) controlled by a variable valve mechanism (100), wherein when the engine is started, the valve timing of the intake valve (35) is set such that the lift / operating angle is a small lift / small operating angle, A starting speed control means (S316) for controlling the starting valve timing so that the closing timing is near bottom dead center is provided.

  By controlling the intake valve at the start valve timing when starting the engine, the amount of air flowing into the cylinder is reduced by the effect of a small lift and small operating angle as the engine speed increases after ignition, and the engine speed increases. Thus, the starting performance can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration of an engine including an intake valve variable valve mechanism.

  The engine 1 includes a crankcase 10, a cylinder block 20 connected to the crankcase 10, and a cylinder head 30 that covers the top of the cylinder block 20.

  A crankshaft 11 is rotatably supported in the crankcase 10. When the engine 1 is started, the crankshaft 11 is given a starting torque by a starter motor 12 via a ring gear 14 of a flywheel 13 connected to one end of the crankshaft 11.

  A plurality of cylinders 21 are formed in the cylinder block 20. In FIG. 1, only one cylinder is shown in order to prevent the drawing from being complicated. A piston 22 is slidably fitted into the cylinder 21. The piston 22 is connected to the crankshaft 11 by a connecting rod 23.

  The cylinder head 30 is formed with an intake passage 32 and an exhaust passage 33 that open to the top wall of the combustion chamber 31, and an ignition plug 34 is provided at the center of the top wall of the combustion chamber 31. The cylinder head 30 is provided with a pair of intake valves 35 that open and close the opening of the intake passage 31 and a pair of exhaust valves 36 that open and close the opening of the exhaust passage 32. In FIG. 1, only one intake valve and exhaust valve are shown in order to prevent the drawing from being complicated. Further, the cylinder head 30 is provided with an intake valve variable valve mechanism 100 that can open and close the intake valve 35 and set the opening and closing timing to an arbitrary timing, and an exhaust camshaft 37 that drives the exhaust valve 36 to open and close. .

  The intake passage 32 is provided with an air cleaner 321, an intake air temperature sensor 322, an air flow sensor 323, and a fuel injection valve 324 in order from the upstream.

  The air cleaner 321 removes foreign substances contained in the air. The intake air temperature sensor 322 detects the temperature of the air taken into the engine 1 (intake air temperature). The air flow meter 323 detects the flow rate (intake amount) of air taken into the engine 1. The fuel injection valve 324 injects fuel according to the engine operating state.

  The exhaust passage 33 is provided with a catalytic converter 331 that removes harmful substances such as hydrocarbons and nitrogen oxides in the exhaust.

  The controller 200 includes a microcomputer that includes a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), a nonvolatile memory 20, and an input / output interface (I / O interface). In addition to the sensor signals described above, the controller 200 includes an engine water temperature sensor 201 that detects the water temperature of the engine 1, an engine oil temperature sensor 202 that detects the oil temperature of the engine 1, and an engine rotation speed that is detected based on the crank angle. Signals from various sensors such as an engine rotation speed sensor 203 that performs an engine start signal and an ignition sensor 204 that detects an engine start signal are input.

  Next, the intake valve variable valve mechanism 100 will be described with reference to FIG. FIG. 2 is a perspective view of the intake valve variable valve mechanism 100.

  The intake valve variable valve mechanism 100 includes a lift / operation angle variable mechanism 110 that changes the lift / operation angle of the intake valve 35, and a lift center angle of the intake valve 35 (a crank angle position at which the intake valve 35 reaches the maximum lift). A phase variable mechanism 140 for advancing or retarding the phase is provided, and the valve timing of the intake valve 35 is variably controlled. In FIG. 2, only a pair of intake valves 35 corresponding to one cylinder and its related parts are shown in a simplified manner.

  First, the configuration of the lift / operating angle variable mechanism 110 will be described.

  A hollow drive shaft 113 extending in the cylinder row direction is provided above the intake valve 35. The drive shaft 113 is linked to the crankshaft 11 by a belt or chain (not shown) via a driven sprocket 142 provided at one end, and rotates around the axis in conjunction with the crankshaft 11.

  A pair of swing cams 120 is attached to the drive shaft 113 so as to be rotatable with respect to the drive shaft 113 for each cylinder. The pair of swing cams 120 swings (up and down) around the drive shaft 113 within a predetermined rotation range, thereby pressing the valve lifter 119 of the intake valve located below it and lifting the intake valve 35 downward. To do. The pair of swing cams 120 are fixed to each other in the same phase by a cylinder or the like.

A cylindrical drive cam 115 is fixed to the outer periphery of the drive shaft 113 by press fitting or the like. The center P ₄ (see FIG. 3) of the drive cam 115 is at a position eccentric from the axis P ₃ (see FIG. 3) of the drive shaft 113 by a predetermined amount. The drive cam 115 is fixed at a position away from the swing cam 120 by a predetermined distance in the axial direction. Then, the base end 125a of the link arm 125 is rotatably fitted to the outer peripheral surface of the drive cam 115.

  A control shaft 116 extends diagonally above the drive shaft 113 in the cylinder row direction in parallel with the drive shaft 113 and is rotatably supported.

  One end of the control shaft 116 is provided with a lift amount control actuator 130 that rotates the control shaft 116 within a predetermined rotation angle range. The lift amount control actuator 130 is controlled by the first hydraulic device 201 based on a control signal from the controller 200 that detects the operating state of the engine 1.

A control cam 117 is fixed to the outer peripheral surface of the control shaft 116 by press fitting or the like. The center P ₁ (see FIG. 3) of the control cam 117 is at a position eccentric from the axis P ₂ (see FIG. 3) of the control shaft 116 by a predetermined amount. A rocker arm 118 is rotatably fitted to the outer peripheral surface of the control cam 117. The rocker arm 118 swings about the axis P ₁ of the control cam 117 as a fulcrum.

  The rocker arm 118 extends in the left-right direction perpendicular to the axial direction around a central base end portion 118a supported by the control cam 117, and has one end 118b and the other end 118c at both ends thereof. The one end 118b and the swing cam 120 are connected by a link member 126, and the other end 118c (see FIG. 3) and the end 125b of the link arm 125 are connected.

  Next, the configuration of the phase variable mechanism 140 will be described.

  The phase variable mechanism 140 includes a phase angle control actuator 141 and a second hydraulic device 202.

  The phase angle control actuator 141 relatively rotates the sprocket 142 and the drive shaft 113 within a predetermined angle range.

  The second hydraulic device 202 controls the phase angle control actuator 141 based on a control signal from the controller 200 that detects the operating state of the engine 1.

  By the hydraulic control to the phase angle control actuator 141 by the second hydraulic device 202, the sprocket 142 and the drive shaft 113 are relatively rotated, and the lift center angle is advanced or retarded.

  Next, the operation of the lift / operating angle variable mechanism 110 will be described in detail.

  3A and 3B are views of the lift / operating angle variable mechanism 110 as viewed in the drive axis direction. FIG. 3A is a view showing the positions of the swing cam 120 when the intake valve 35 is at the zero lift when the swing cam 120 is at the minimum swing and at the maximum swing. FIG. 3B is a diagram showing the positions of the swing cam 120 when the intake valve 35 is fully lifted when the swing cam 120 is at the minimum swing and at the maximum swing.

  Here, the time of zero lift of the intake valve means that the intake valve 35 does not lift (that is, the lift amount of the intake valve is zero). In addition, when the intake valve is fully lifted, the intake valve 35 has the maximum lift amount.

As shown in FIG. 3A, the center P ₁ of the control cam 117 is located above the axis P ₂ of the control shaft 116, and the thick portion 117 a of the control cam is located above the control shaft 116. In this state, the rocker arm 118 is positioned upward as a whole, and the end 120a of the swing cam 120 is relatively lifted upward. That is, the initial position of the swing cam 120 is inclined in a direction in which the cam surface 120b is separated from the valve lifter 119 (see the left side of FIG. 3A). Therefore, when the swing cam 120 swings with the rotation of the drive shaft 113, the base circle surface 120c continues to contact the valve lifter for a long time, and the period during which the cam surface 120b contacts the valve lifter is shortened. For this reason, the maximum lift amount of the intake valve 35 is reduced (see the right side of FIG. 3A). Further, the crank angle section from the opening timing to the closing timing of the intake valve 35, that is, the operating angle of the intake valve 35 is also reduced.

On the other hand, as shown in FIG. 3B, the center P ₁ of the control cam 117 is located below the axis P ₂ of the control shaft 116, and the thick portion 117 a of the control cam is located below the control shaft 116. When positioned, the rocker arm 118 is positioned downward as a whole, and the end 120a of the swing cam 120 is relatively pushed downward. That is, the initial position of the swing cam 120 is inclined in a direction in which the cam surface 120b approaches the valve lifter 119 (see the left side of FIG. 3B). Therefore, when the swing cam 120 swings with the rotation of the drive shaft 113, the portion that contacts the valve lifter 119 immediately shifts from the base circle surface 120c to the cam surface 120b. For this reason, the maximum lift amount of the intake valve 35 is increased (see the right side of FIG. 3B). In addition, the operating angle of the intake valve 35 is increased.

  FIG. 4 is a diagram for explaining the operation of the intake valve variable valve mechanism 100.

  Since the initial position of the control cam 117 described above with reference to FIG. 3 can be continuously changed, the valve lift characteristic of the intake valve 35 is continuously changed accordingly. That is, as shown by the solid line in FIG. 4, the intake valve variable valve mechanism 100 continuously increases and decreases the lift amount and the operation angle of the intake valve 35 simultaneously by the lift / operation angle variable mechanism 110. be able to. Although depending on the layout of each part, for example, the opening timing and closing timing of the intake valve 35 change substantially symmetrically with changes in the lift amount and operating angle of the intake valve 35.

  Furthermore, as shown by the broken line in FIG. 4, the intake valve variable valve mechanism 100 can advance or retard the lift center angle by the phase variable mechanism 140.

  In this way, by combining the lift / operating angle variable mechanism 110 and the phase variable mechanism 140, the intake valve variable valve mechanism 100 can open and close the intake valve 35 at an arbitrary crank angle position, and the intake valve 35 is closed. Can be set at any time. That is, the valve timing of the intake valve 35 can be set arbitrarily.

FIG. 5 is a graph showing the relationship between the lift amount and operating angle of the intake valve 35 and the engine volumetric efficiency η _v .

  As shown in FIG. 5, when the lift is small and the operating angle is small, the volume efficiency is higher when the engine speed is low (around 200 rpm) than when the engine speed is high (around 800 rpm). is there. Therefore, when the engine is started, the volumetric efficiency is higher when the lift amount of the intake valve 35 is set to a small lift rather than a large lift. Further, if the lift amount is set to a small lift at the time of starting the engine, the volume efficiency decreases as the engine rotational speed increases after ignition, so that it is possible to suppress engine blow-up.

  Next, when the lift amount and the operating angle are increased, the volumetric efficiency at each engine rotation speed becomes substantially the same, but the volumetric efficiency decreases because the closing timing of the intake valve 35 is delayed from the bottom dead center. .

  Since there is such a relationship between the lift amount and operating angle of the intake valve 35 and the engine volumetric efficiency, by setting the lift amount and operating angle to a small lift / small operating angle in advance when starting the engine, Since the volumetric efficiency is increased and the compression temperature is increased, the ignition performance is improved. At the same time, the closing timing of the intake valve 35 can be set around the bottom dead center, and the actual compression ratio increases and the compression temperature increases, so that the ignition performance can be further improved.

  In addition, by setting the lift amount and the operating angle to a small lift / small operating angle in advance when starting the engine, the air flow rate flowing into the cylinder is reduced, so that the volume efficiency decreases as the engine speed increases. Thereby, the racing at the time of engine starting can be suppressed. On the other hand, when the engine rotation speed cannot reach the idle rotation speed after ignition at a predetermined lift amount and operating angle at the time of starting the engine due to the effect of suppressing the rotational blow-up, the lift amount of the intake valve 35 and Starting torque can be secured by setting the operating angle to a large lift / large operating angle.

  In this way, if the lift amount and operating angle of the intake valve 35 at the time of engine start are set in the region surrounded by the solid line in FIG. 5, the increase speed of the engine rotation speed is detected, and the intake valve can be used as necessary. The starting torque can be controlled by controlling the variable valve mechanism 100.

  Hereinafter, the starting torque control by the intake valve variable valve mechanism 100 at the time of starting the engine will be described.

  FIG. 6 is a flowchart showing engine start time control of the intake valve variable valve mechanism 100. The controller 200 repeatedly executes this routine every predetermined time (for example, 10 ms).

  In step S1, the controller 200 reads an engine start signal. The engine start signal is detected by the ignition sensor 204, and is turned ON when the engine is started by the driver's key operation.

  In step S2, the controller 200 determines whether or not the engine start signal is ON. The controller 200 proceeds to step S3 if the engine start signal is ON, and proceeds to step S4 if it is OFF.

  In step S3, the controller 200 executes starting torque control. Specific processing contents will be described with reference to FIG.

  In step S4, the controller 200 executes idle rotation speed control. Specifically, the valve timing, the fuel injection amount, and the ignition timing of the intake valve 35 are controlled so that the engine rotation speed maintains the idle rotation speed.

  FIG. 7 is a flowchart illustrating the starting torque control according to the first embodiment of the present invention.

  In step S311, the controller 200 reads the engine oil water temperature and the intake air temperature.

  In step S312, the controller 200 drives the starter motor 12 to crank the crankshaft 11.

  In step S313, the controller 200 reads the engine rotation speed.

  In step S314, the controller 200 reads a variable valve drive permission signal. The variable valve drive permission signal is ON when the engine is rotating.

  In step S315, the controller 200 determines whether or not the variable valve drive permission signal is ON. If the variable valve drive permission signal is ON, the controller 200 proceeds to step S316, and if it is OFF, ends the current process.

  In step S316, the controller 200 controls the intake valve variable valve mechanism 100, and the lift amount and operating angle of the intake valve 35 are determined in advance as shown in FIG. Control is performed in a small lift / small operating angle region (hereinafter referred to as “start valve timing”) in which start torque control is possible.

  In step S317, the controller 200 determines whether or not the increase value of the engine rotation speed after ignition (hereinafter referred to as “engine rotation increase speed”) is within a predetermined range. Specifically, it is determined whether or not the difference between the engine rotational speed read in the current process and the engine rotational speed read in the previous process is within a predetermined range. The controller 200 ends the current process if the engine rotation speed increase is within the predetermined range, and proceeds to step S318 if not.

  In step S318, the controller 200 controls the intake valve variable valve mechanism 100 in accordance with the deviation between the predetermined target engine rotation increase speed and the actual engine rotation increase speed. Specifically, when the engine rotation speed increase is less than the predetermined value α, the starting torque is insufficient, so the starting torque is ensured by increasing the lift amount and operating angle of the intake valve 35. On the other hand, when the engine speed increase rate is larger than the predetermined value β, the engine is blowing up, so that the lift amount and the operating angle of the intake valve 35 are reduced in order to reduce the intake amount by reducing the intake amount.

  FIG. 8 is a time chart of the starting torque control according to the first embodiment of the present invention.

  When the engine start signal is turned on at time t1 (FIG. 7 (A); Yes in S2), cranking is started and the engine speed is increased (FIG. 7 (C); S312).

  Since the engine rotation is started at time t2, the drive of the intake valve variable valve mechanism 100 is permitted (FIGS. 7B and 7C; Yes in S315), and the valve timing of the intake valve 35 becomes the start valve timing. It is set (FIG. 7 (D); S316).

  At time t3, when the engine speed is ignited and the engine speed increases (FIG. 7C), based on the detected increase value of the engine speed (engine speed increase speed), the intake valve 35 in the interval from time t3 to t4. The valve timing is controlled (FIGS. 7C and 7D; No in S317 or Yes in S317, S318). In addition, since this time chart shows the case where the engine speed increase rate is within a predetermined range, the valve timing of the intake valve 35 is not changed in the section from time t3 to t4.

  When the engine start signal is turned off at time t4, the idle rotation speed control is started (FIG. 7A; No in S2, S4).

  According to the embodiment described above, in the internal combustion engine that controls the in-cylinder inflow intake amount by the variable valve mechanism, when the engine is started, the lift amount and the operating angle are set to the small lift and the small operating angle in advance. . Thereby, the volumetric efficiency at the time of starting the engine is increased and the compression temperature is increased, so that the ignition performance is improved. At the same time, since the closing timing of the intake valve 35 can be set around the bottom dead center, the actual compression ratio is increased, the compression temperature is increased, and the ignition performance can be further improved.

  In addition, by setting the lift amount and the operating angle to a small lift / small operating angle in advance when starting the engine, the air flow rate flowing into the cylinder is reduced, so that the volume efficiency decreases as the engine speed increases. Thereby, the racing at the time of engine starting can be suppressed, and unpleasant vibration at the time of starting can be suppressed. On the other hand, when the engine rotation speed cannot reach the idle rotation speed after ignition at a predetermined lift amount and operating angle at the time of starting the engine due to the effect of suppressing the rotational blow-up, the lift amount of the intake valve 35 and Starting torque can be secured by setting the operating angle to a large lift / large operating angle.

  Thus, the starting torque can be controlled by controlling the intake valve variable valve mechanism 100 according to the increase value of the engine rotation speed.

(Second Embodiment)
Next, the starting torque control according to the second embodiment of the present invention will be described. The starting torque control according to the second embodiment of the present invention is the first embodiment in that it determines the possibility of occurrence of pre-ignition (fuel is ignited before the ignition timing by the compression operation at the time of starting the engine) at the time of starting the engine. This is different from the starting torque control by. Hereinafter, the difference will be mainly described. In the following embodiments, the same reference numerals are used for portions that perform the same functions as those in the first embodiment described above, and repeated descriptions are omitted as appropriate.

  FIG. 9 is a graph showing the relationship between the lift amount and operating angle of the intake valve 35 and the in-cylinder compression temperature during cranking.

  When the valve timing of the intake valve 35 at the time of engine start is set so that a small lift, a small operating angle and a closing timing are around the bottom dead center (starting initial position in FIG. 9), especially when the intake air temperature is high, the piston By the compression operation of 22, the in-cylinder temperature may exceed the pre-ignition generation temperature. Hereinafter, the pre-ignition generated when the engine is started is abbreviated as “starting pre-gage” as necessary.

  The occurrence of such a start plague causes deterioration of fuel consumption and engine damage, and is desirably avoided. Therefore, in the present embodiment, at the time of engine start, the possibility of occurrence of the start pre-ignition is determined from the engine oil water temperature and the intake air temperature. The mechanism 100 is controlled. Hereinafter, the starting torque control for preventing the occurrence of the starting plague will be described.

  FIG. 10 is a flowchart illustrating the starting torque control according to the second embodiment of the present invention. In addition, since the process performed by S311 to S318 is the same as that of 1st Embodiment, description is abbreviate | omitted here.

  In step S321, the controller 200 determines whether or not there is a possibility that a start plague may occur based on the engine water temperature and the intake air temperature. The controller 200 sets the start plague occurrence flag to 1 when it is determined that the start plague may occur, and sets the start plague occurrence flag to 0 when it is determined that there is no possibility.

  In step S322, the controller 200 determines whether or not the start pre-ignition generation flag is 1. The controller 200 moves the process to step S323 if the start pre-ignition occurrence flag is 1, and moves the process to S316 if it is 0.

  In step S323, the controller 200 controls the intake valve variable valve mechanism 100 so that the start pre-ignition avoidance valve timing is reached. Specifically, the closing timing of the intake valve 35 is retarded by changing the lift amount and operating angle of the intake valve 35 from the start valve timing (starting initial position) to the large lift / large operating angle side. Thereby, since the volumetric efficiency at the time of engine start-up falls, compression temperature falls and it can avoid a start plague. Note that the start plague can be avoided even when the initial start position is changed to the small lift / small operating angle side. This is because the compression temperature can also be lowered by reducing the in-cylinder intake air.

  In step S324, when the controller 200 determines that the start plague cannot be avoided only by changing the valve timing of the intake valve 35, the controller 200 avoids the start plague by fuel injection control. Specifically, the fuel injection timing is retarded from the exhaust stroke to the intake stroke. As a result, the compression temperature can be lowered by the latent heat of vaporization, and the start plague can be avoided.

  FIG. 11 is a time chart of the starting torque control according to the second embodiment of the present invention.

  When the engine start signal is turned on at time t1 (FIG. 11 (A); Yes in S2), the engine oil water temperature and the intake air temperature are read (S311), and whether or not a start plague is generated based on these detection signals. Is determined (FIG. 11B; S321). Further, cranking is started and the engine rotation speed is increased (FIG. 11D; S312).

  Since engine rotation is started at time t2, the drive of the intake valve variable valve mechanism 100 is permitted (FIGS. 11C and 11D; Yes in S315), and the valve timing of the intake valve 35 is determined to be the start pre-gage determination flag. Is set according to the value of (S322). In this time chart, since the start preg determination flag is set to 1 (FIG. 11 (B)), the valve timing of the intake valve 35 is the start preauging valve timing (larger lift / large operating angle than the start valve timing). Side valve timing) (FIG. 11E; Yes in S322, S323). Further, if the start pre-ignition cannot be avoided by simply changing the valve timing of the intake valve 35 to the start pre-ignition avoidance valve timing, the fuel injection timing is also set to the intake stroke injection at the same time (FIG. 11 (F); S324).

  When the engine rotational speed reaches a predetermined engine rotational speed at time t3 and the engine start signal is turned OFF, idle rotational speed control is started (FIG. 11A; No in S2, S4).

  According to the present embodiment described above, in addition to the effects of the first embodiment, the compression temperature is lowered by controlling the valve timing of the intake valve 35 when pre-ignition may occur at the time of engine start. And pre-ignition can be avoided.

  It should be noted that the present invention is not limited to the embodiment described above, and various modifications and changes can be made within the scope of the technical idea, and it is obvious that these are also included in the technical scope of the present invention.

  For example, in the second embodiment, when there is a possibility that pre-ignition may occur at the time of engine start, the compression temperature is lowered by controlling both the valve timing of the intake valve and the fuel injection timing, and pre-ignition is performed. Although avoided, only one of them may be controlled.

It is a figure which shows the structure of the engine provided with the intake valve variable valve mechanism. It is a perspective view of an intake valve variable valve mechanism. It is a drive-axis direction view of a lift / operation angle variable mechanism. It is a figure explaining the effect | action of an intake valve variable valve mechanism. It is the figure which showed the relationship between the lift amount and operating angle of an intake valve, and engine volume efficiency. It is a flowchart which shows the engine start time control of an intake valve variable valve mechanism. It is a flowchart explaining the starting torque control by 1st Embodiment of this invention. It is a time chart of starting torque control by a 1st embodiment of the present invention. It is the figure which showed the relationship between the lift amount and operating angle of an intake valve, and the cylinder compression temperature at the time of cranking. It is a flowchart explaining the starting torque control by 2nd Embodiment of this invention. It is a time chart of the starting torque control by 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 35 Intake valve 100 Variable valve mechanism 110 Lift / operating angle variable mechanism 140 Phase variable mechanism 201 Engine water temperature sensor (engine temperature detection means)
202 Engine oil temperature sensor (engine temperature detection means)
203 Engine rotational speed sensor (rotational speed detection means)
322 Intake air temperature sensor (intake air temperature detection means)
S316, S317, S318 Start-up rotation speed control means S321 Start pre-ignition generation determination means S323 Start-up rotation speed control means S324 Start-up rotation speed control means

Claims (8)

A lift operating angle variable mechanism that can simultaneously and continuously expand and contract the lift / operating angle of the intake valve, and a phase variable mechanism that can retard the phase of the lift center angle of the intake valve. An internal combustion engine start control device that has a variable valve mechanism that can variably control the valve timing of the intake valve, and that controls the in-cylinder inflow intake air amount by the variable valve mechanism;
It is provided with a starting speed control means for controlling the valve timing of the intake valve to a starting valve timing at which the lift / operating angle is a small lift / small operating angle and the closing timing is near the bottom dead center when the engine is started. A start control device for an internal combustion engine characterized by the above. Rotation speed detection means for detecting the rotation speed of the internal combustion engine;
Engine rotation increase speed calculating means for calculating the increase speed of the rotation speed,
The starting speed control means is configured to increase the engine speed and a predetermined target engine speed increase when the increasing speed is out of a predetermined range after the first explosion until the predetermined idle rotating speed is reached. 2. The start control device for an internal combustion engine according to claim 1, wherein the valve timing of the intake valve is corrected based on a deviation from a speed so that the increase speed becomes the target engine rotation increase speed. The starting rotational speed control means makes the lift / operation angle of the intake valve larger than the lift / operation angle at the start valve timing when the rising speed is smaller than the minimum value of the predetermined range. The start control device for an internal combustion engine according to claim 2. The starting rotational speed control means makes the lift / operating angle of the intake valve smaller than the lift / operating angle at the start valve timing when the rising speed is larger than the maximum value in the predetermined range. A start control device for an internal combustion engine according to claim 2 or 3. Engine temperature detecting means for detecting the engine temperature;
Intake air temperature detecting means for detecting the temperature of air sucked into the engine;
Starting pre-ignition generation determining means for determining whether or not pre-ignition occurs at the time of starting the engine from detection values of the engine temperature detecting means and the intake air temperature detecting means,
When the start pre-ignition generation determining means determines that pre-ignition has occurred, the starting rotational speed control means reduces the pre-ignition by reducing the in-cylinder inflow air amount less than the in-cylinder inflow air amount at the start valve timing. 2. The start control device for an internal combustion engine according to claim 1, wherein the valve timing of the intake valve is corrected so as to avoid it. The starting rotational speed control means corrects the valve timing of the intake valve so as to avoid pre-ignition so that the closing timing of the intake valve is retarded from the closing timing in the starting valve timing. The start control device for an internal combustion engine according to claim 5. The starting rotational speed control means corrects the valve timing of the intake valve so as to avoid the pre-ignition so that the lift / operating angle of the intake valve is smaller than the lift / operating angle at the start valve timing. The start control device for an internal combustion engine according to claim 5. Engine temperature detecting means for detecting the engine temperature;
Intake air temperature detecting means for detecting the temperature of air sucked into the engine;
Starting pre-ignition occurrence determining means for determining whether or not pre-ignition is generated at the time of starting the engine, from detection values of the engine temperature detecting means and the intake air temperature detecting means,
2. The start control device for an internal combustion engine according to claim 1, wherein the starting rotation speed control means sets the fuel injection timing as an intake stroke when the start pre-ignition generation determination means determines that pre-ignition has occurred. .

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